Most samples cannot be build on some environments because they depend
on CC_CAN_LINK, which is set according to the result of
scripts/cc-can-link.sh called by cc_can_link_user.
Because cc-can-link.sh must now build without warning, it may fail
because it is calling printf() with an empty string:
+ cat
+ gcc -m32 -Werror -Wl,--fatal-warnings -x c - -o /dev/null
<stdin>: In function ‘main’:
<stdin>:4:9: error: zero-length gnu_printf format string [-Werror=format-zero-length]
cc1: all warnings being treated as errors
Fix this warning and the samples build by actually printing something.
Cc: stable@vger.kernel.org
Fixes: d81d9d389b ("kbuild: don't enable CC_CAN_LINK if the dummy program generates warnings")
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Reviewed-by: Nicolas Schier <nsc@kernel.org>
Reviewed-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Link: https://patch.msgid.link/20260212133544.1331437-1-mic@digikod.net
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
It is possible that the kernel toolchain generates warnings when used
together with the system toolchain. This happens for example when the
older kernel toolchain does not handle new versions of sframe debug
information. While these warnings where ignored during the evaluation
of CC_CAN_LINK, together with CONFIG_WERROR the actual userprog build
will later fail.
Example warning:
.../x86_64-linux/13.2.0/../../../../x86_64-linux/bin/ld:
error in /lib/../lib64/crt1.o(.sframe); no .sframe will be created
collect2: error: ld returned 1 exit status
Make sure that the very simple example program does not generate
warnings already to avoid breaking the userprog compilations.
Fixes: ec4a3992bc ("kbuild: respect CONFIG_WERROR for linker and assembler")
Fixes: 3f0ff4cc6f ("kbuild: respect CONFIG_WERROR for userprogs")
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Reviewed-by: Nicolas Schier <nsc@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Link: https://patch.msgid.link/20251114-kbuild-userprogs-bits-v3-1-4dee0d74d439@linutronix.de
Signed-off-by: Nicolas Schier <nsc@kernel.org>
With the brand-new syntax extension of Kconfig, we can directly
check the compiler capability in the configuration phase.
If the cc-can-link.sh fails, the BPFILTER_UMH is automatically
hidden by the dependency.
I also deleted 'default n', which is no-op.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
check that CC can build executables and use that compiler instead of HOSTCC
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
